Scales Used In Batching Plants

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Batching plants make a suitable mix for concrete and other composite materials through the use of equipment to measure and combine specific materials in the right proportions. Included in this equipment are a number of different types of scales including beam scales, aggregate scales, tank scales, floor scales and a wide variety of different types of industrial scales with digital indicators.

The Batching Process
Measuring and mixing of ingredients for this process is called batching. When it is done by hand, the batch’s size is determined by the number of workers available to use the required mixing tools, the size of the container used, and the speed that is required. Otherwise, the mixing machine’s capacity will regulate batch size, which is often described in cubic feet of finished product. Usually, there will be several separate hoppers that hold the different ingredients, often referred to as fine and course aggregates. Sometimes ingredients are further divided inside the hoppers in different compartments according to aggregate type. These hoppers discharge their materials ...
... into weigh boxes, where they are weighed in the boxes on a beam scale before they advance to batch trucks or mixers. There are a wide variety of other types of composite materials that are produced by the batch process, including plastics, pharmaceuticals, chemicals, and food products.

Beam Scale
A traditional, put now primarily outmoded method uses beam scales which are portable (usually) balances which are outfitted with unequal arms pivoting on a bar. They are frequently used in industrial settings such as steelyards, and are also found in batching plants. When a precise weight of ingredient (aggregate) is needed, a worker in a batching plant will often use a beam scale to determine the appropriate amount. The weighing process is simple: the worker opens the storage hopper’s discharge chute, which pours aggregate into the weigh box until the scale beam rises to the proper height. Then the worker closes the storage hopper’s discharge chute and opens the weigh box’s discharge chute, and the ingredients make their way to their final destination †the mixer or batch truck.

Industrial Scales with Digital Indicators
Industrial scales with digital indicators are the more modern method now used in batching plants. These digital indicators can be used in batching plants with a number of different types of industrial scales, including platform scales, crane scales and drum scales. Digital indicators for industrial scales perform automated batching operations with ease. Automated batching done with industrial scales typically works with a method where for each aggregate, a different set point value is assigned. The set point output will stop the feed of the first material after the first level is completed and then second set point will begin, and so on until all the aggregates and ingredients have been properly dispensed in the correct proportions.

These programmable indicators are usually high resolution, have a numeric keypad that can enter and track set points for batching, as well as tare and unit conversion functions. There are two types of batch weighing methods: normal and loss in weight batching. Loss in weight batching modes are used when the container is weighed as the batch is started and ingredients are no longer dispensed when the goal weight is reached. Some digital indicators have high sampling speeds of up to 70 times per second. These indicators are usually outfitted with at least an RS-232 connection, but many are choosing indicators that have USB or Ethernet ports instead, because those do not require close proximity to a computer.